Spirally-wound easy-open container having a score cut opening panel

Abstract

An easy-open container has a spirally-wound paperboard bodywall layer, interior barrier liner layer and outer label layer forming as easy-open seam extending spirally between the ends of the container. Easy-opening of the container is enhanced by the provision of pull tabs formed by superimposed and bonded longitudinal edge portions of the bodywall layer and label layer and an easy-open panel formed by diverging lines of score cuts formed in the bodywall layer to initiate and aid in easy-opening of the container along the spiral seam.

What is claimed: 
     
       1. A method of manufacturing an easy-open container comprising the steps of: providing a flexible barrier liner layer in strip form, feeding the liner layer strip to a mandrel, and spirally-winding the liner layer strip on the mandrel while forming overlapping liner layer edge portions;   providing a paperboard bodywall layer in strip form, feeding the bodywall layer strip to the mandrel while forming spaced tab cuts through the bodywall layer and extending inwardly from one outer longitudinal edge thereof to define an easy-open pull tab and simultaneously forming diverging lines of score cuts through the bodywall layer strip and each extending inwardly from respective tab cuts to the other outer longitudinal edge of the bodywall layer strip to define an easy-open panel, and spirally-winding and positioning the bodywall layer strip onto the spirally-wound liner layer on the mandrel in a manner such that the longitudinal edges of the bodywall layer strip are adjacent each other to form a continuous tube having a spiral seam extending the length thereof;   providing a flexible label layer in strip form, feeding the label layer strip to the mandrel while forming spaced tab cuts through the label layer strip and extending inwardly from one outer longitudinal edge thereof to define an easy-open pull tab and spirally-winding the label layer strip onto the continuous tube on the mandrel with the longitudinal edges of the label layer strip in overlapped relation and positioned to one side of the spiral seam in the bodywall layer and while positioning the pull tab in the label layer in superimposed position over the pull tab in the bodywall layer;   controlling tension on the bodywall layer strip and on the label layer strip during the steps of feeding such strips to the mandrel to ensure the superimposed position of the pull tabs in such strips; and   cutting the thus wound tube into individual container lengths.   
     
     
       2. A method, as set forth in claim 1, in which said step of feeding the label layer strip to the mandrel further includes applying a high strength bonding material in the form of a permanent adhesive to a bottom surface of the label layer strip while leaving an edge portion of the one outer longitudinal edge having the tab cuts therein, but of a narrower width than the length of the tab cuts, uncoated with the high strength bonding means so that the overlapped edges of the label layer strip will not have high strength bonding means therebetween. 
     
     
       3. A method, as set forth in claim 2, in which said step of feeding the label layer strip to the mandrel further includes folding over onto itself the one longitudinal edge portion in which the spaced tab cuts are formed and applying a high strength bonding means in the form of a permanent adhesive between the folded over longitudinal edge portions and applying a low strength bonding means in the form of a frangible adhesive along that surface of the one longitudinal edge portion which is to be overlapped with the other longitudinal edge portion during spiral winding. 
     
     
       4. A method, as set forth in claim 1, in which said step of feeding the liner layer strip to a mandrel further includes folding over one of the longitudinal edge portions onto itself and in which the step of spirally winding the liner layer strip on the mandrel while forming overlapping liner layer edge portions further includes heat sealing of the overlapping liner layer edge portions to provide a low strength bonding means therebetween and an expandable joint in the spirally-wound liner layer to facilitate easy opening of the container. 
     
     
       5. A method, as set forth in claim 4, in which said step of feeding the bodywall layer strip to the mandrel includes applying a high strength bonding means in the form of a permanent adhesive along the surface thereof to be spirally-wound onto the spirally-wound liner layer except in an area of the surface of the bodywall layer strip which is spirally-wound onto the expandable joint formed in the liner layer. 
     
     
       6. A method, as set forth in claim 1, 2, 3, 4 or 5, in which said steps of forming spaced tab cuts and diverging lines of score cuts through the bodywall layer strip during feeding of such strip to the mandrel comprises rotary dye cutting of the space tab cuts and diverging lines of score cuts.